That's interesting. It's stamped in reverse from all the wheel's I have.

Where's the valve stem hole in relation to the stamping? All of the wheel's in my list have the letter's/number's stamped with some on either side of the hole. There's no hole in your pic, and it should be between the 21 and the 4.......

Thanks for your interesting input.............WE have no doubt that LATE June-July 70's and ALL 71 Z's had the 13/16th wheel.....(Go ahead send your factual original wheel KNOWN to be on Original car 5/8? examples) ...........

You must honestly think that your wheel examples were born on your date example car...........

We are mainly looking for more May-July 70 examples to determine a Norwood AND Los Angeles changeover.........

That's interesting. It's stamped in reverse from all the wheel's I have.

Where's the valve stem hole in relation to the stamping? All of the wheel's in my list have the letter's/number's stamped with some on either side of the hole. There's no hole in your pic, and it should be between the 21 and the 4.......

One thing not being discussed is the date of the change on the spokes . . . some being rounded where they meet the outer rim and the other being flat faced.
I believe the change occurred when the outer lip and trim ring fit changed around 77 or 78 but I don't know for sure.

This would be an easy judging distinction for identifying wrong wheels (at least wrong or correct year wheels.).